Despite improvements in rechargeable battery technology, battery capability continues to limit performance of mobile electronic devices. In particular, limited energy capacity results in relatively short device run-times, of, for example, only a few hours, between recharging or switching batteries. In addition, functional integration, such as in the example of integrating camera functions onto a cellular telephone handset, results in popular multiple function devices yet may increase energy consumption. Video encoding/decoding operations such as MPEG, H.264, VC-1 based encoding and/or decoding or other video coding circuits can consume limited battery power.
Power conservation techniques may be used to compensate for battery limitations in battery-powered devices. For example, low power modes may be used to conserve power by selectively shutting down certain components or functional blocks within components. Alternatively, power may be saved by reducing power supply voltages or clocking frequencies. Typical low power modes are entered either by direct operator interaction, such as by placing the device to low power mode, or by a triggering event. A triggering event may occur when, for example, the battery capacity drops below a certain threshold. Alternatively, a low power mode may be triggered when certain functional blocks in the device have not been used or accessed for some period of time. These triggering events may be useful for conserving battery power; however, each is reactive rather than proactive. That is, significant battery may be consumed prior to triggering. As a result, the triggering techniques may not be sufficient to provide sufficient energy conservation in all cases. Since video decoders in battery-powered devices can consume significant energy, improved video decoders with reduce power consumption and methods thereof would be desirable.